Method and apparatus for shipping incompatible materials in the same compartment



Sept. 1, 1964 M. D. HOWCROFT 3,147,041

METHOD AND APPARATUS FOR SHIPPING INCOMPATIBLE MATERIALS IN THE SAMECOMPARTMENT Filed May 29, 1961 INVENTOR. E I E. z MAX D. HOWCROFT ATTORNEYS United States Patent 3,147,041 METHOD AND APPARATUS FOR SHEPINGIN- COMPATIBLE MATERIALS IN THE SAME COM- PARTMENT Max D. Howcroft, 1716Crestview Drive, Modesto, Calif. Filed May 29, 1961, Ser. No. 113,353 8Claims. (Cl. 30253) This invention relates to improvements in a methodand apparatus for shipping incompatible materials in the samecompartment.

A serious economic problem has arisen in connection with certaincarriers such as railway tankcars, tanker ships, tank trucks, gondolacars, and the like which are used to transport oily, corrosive,odoriferous and similar materials. Because these materials areincompatible with and tend to contaminate many other materials normallyshipped in the same type of carrier, it is often necessary for thecarrier to return empty. For example oil and other refinery products areoften shipped in tankcars from the Texas oil fields to the Midwest andthe tankcars are subsequently returned empty. At the same time grain isshipped in boxcars or other types of railway cars to Texas, and becauseof lack of suitable cargo return empty to the Midwest. Obviously, if thegrain could be shipped in the tankcars returning to Texas, significantsavings would be effected. This has heretofore been impractical due tothe well known propensity of grain to take on the strong odors of oiland like products.

The same situation applies to other types of carriers moving betweenother areas. Likewise, storing of commodities would be greatlysimplified and expedited if they could be stored at different times inthe same compartment.

The present invention contemplates a method and apparatus for shippingflowable materials in the same compartment either at the same time or atdiiferent times in such manner that the materials are protected fromcontamination. For this purpose the invention envisions a bag-like linerseparate from but insertible into the compartment and adapted to containand protect the material being shipped. For low cost and strengthcombined with imperviousness to odors, etc., I prefer to form the bagliners of readily available synthetic resin plastics.

Where an elongated compartment such as that provided by tankcars isbeing used, problems arise in filling the relatively inaccessible endsof the compartment so as to utilize completely its full volumetriccapacity. It is necessary to convey the material into the ends of thecompartment and I have found the bag liner has a strong tendency tointerfere with this procedure. To overcome this problem I inflate thebag with air so as to support the walls thereof in distended conditionout of the way of whatever conveying means is being used.

Another problem arises in emptying the bag liners, also as a result ofthe thin, flexible nature of the bag walls. Unless otherwise supported,the bag tends to collapse upon and interfere with the operation of theremoval conveyor. I have found that I can completely eliminate thisproblem by adding sufiicient air to maintain the bag in inflatedcondition during the removal of the material therefrom.

Accordingly it is a principal object of the present invention to providea method and apparatus for shipping flowable materials in the samecompartment in which the material being shipped may be quickly andeasily loaded and removed but will be completely sealed off from theinner surfaces of the compartment.

Another object of the invention is to provide a method and apparatus ofthe character described incorporating a flexible bag liner not directlyconnected to the compartment walls but which is supported thereagainstduring the loading and unloading operations.

A further object of the invention is to provide an apparatus of thecharacter described in which air is introduced into the bag liner andthe latter is maintained in inflated condition by restricting the flowof air from the liner.

A still further object of the invention is to provide an apparatus ofthe character described in which the air supply is provided by thepneumatic conveyor used to load the flowable material into the bag.

Another object of the invention is to provide an apparatus of thecharacter described which incorporates additional means for aiding inremoving the flowable material from the ends of elongated compartments.

Further objects and advantages of my invention will be apparent as thespecification progresses, and the new and useful features of my methodand apparatus for shipping incompatible materials in the samecompartment will be fully defined in the claims attached hereto.

The preferred forms of my invention are illustrated in the accompanyingdrawing forming part of this application, in which:

FIGURE 1 is a side elevational view of a railway tankcar in which aloading apparatus constructed in accordance with the present inventionis operatively positioned and in which portions of the tankcar andapparatus are broken away and shown in section to illustrate internaldetails;

FIGURE 2, a side elevational view of one end of a tankcar takensimilarly to that of FIGURE 1 but illustrating apparatus for removingthe flowable material therefrom;

FIGURE 3, an enlarged fragmentary detail view of a device for eifectingan air-tight connection between the bag liner and a pneumatic conveyorconduit; and

FIGURE 4, a fragmentary side elevational view of an end of a tankcarincorporating a modified form of the apparatus of FIGURE 2.

While I have shown only the preferred forms of my invention, it shouldbe understood that various changes or modifications may be made withinthe scope of the claims attached hereto without departing from thespirit of the invention.

Referring to the drawings in detail, it will be seen that the apparatusof the present invention includes a bag 11 adapted for containing aflowable material such as grain 12 and having thin, flexible walls 13impervious to odors and contaminants and formed for positioning withinthe compartment, together with means 14 for supporting the bag walls 13during movement of the flowable material into and out of the bag. Alsoincorporated in the apparatus is a conveyor means 16 for selectivelymoving the material 12 into and out of the bag.

The material of which the bag 11 is formed is important to thesuccessful operation of the invention and preferably consists of asynthetic resin plastic having certain desired properties. Theparticular properties required will vary somewhat with the nature of thecommodity being shipped, the size and shape of the compartment, andspecial requirements such as corrosion resistance, etc. However, certainproperties are common to all forms of the invention.

For economy in manufacture, ease in handling Era space requirements, thewalls 13 of the bag should be very thin and flexible. This is madepossible by the fact .that the bag walls are supported against outwardmovement by the walls of the compartment and are supported againstinward movement by the means 14 during loading and unloading and by theflowable material during shipping.

For most purposes a polyethylene material several thousandths of an inchthick will be adequate. Where the compartment is large or the materialbeing carried presents sharp and jagged edges, the bag may be formed ofthe polyester film produced by reacting terephthalic acid With ethyleneglycol and commonly known by the Du Pont trade name Mylar. Whereincreased chemical inertness and resistance to corrosion is required thefilm may be formed of or coated with polytetrafluoro ethylene, commonlyknown as Teflon.

The extreme thinness of the wall 13 makes it possible to collapse thebag completely and leave it in place in a compartment such as theinterior of a railway tankcar 17 when the latter is being used in itsnormal capacity for transporting liquids. The collapsed bag takes upvery little space and when the car is empty the bag may readily beinflated to assume its correct position in the tankcar.

In accordance with the present invention the means 14 for supporting thebag walls 13 includes a conduit 18 communicating with the interior ofthe bag 11 and adapted for connection to a source of air under pressuresuch as a blower 19. The conduit 18 has a flow capacity sufficient formaintaining the bag 11 in inflated condition during the movement of theflowable material 12 into and out of the bag by the conveyor means 16without obstruction by the bag walls 13. This makes it possible toutilize the full volumetric capacity of elongated compartments such asare found in the tankcars 17.

While any suitable conveyor means 16 may be employed in the apparatus, Ihave found that a pneumatic conveyor means provides several unexpectedadvantages. For example in the form of the invention shown in FIG- URE 1and utilized for filling the tankcar 17 with grain 12 or other flowablematerial, the functions of the conduit 18 and the conveyor means 16 arecombined. As depicted more or less schematically at the upper portion ofFIGURE 1, a grain hopper 21 may be mounted to feed into the conduit 18so that the grain is entrained upon the air blast passing through. Thegrain is conveyed into the bag 11 by an extension 22 of the conduit 18which is made flexible so as to direct the stream of grain to thedesired location. With this construction the stream of air passingthrough extension 22 serves both to inflate the bag and to propel thegrain into the ends of the compartment.

FIGURE 3 illustrates a convenient method of sealing the bag 11 to theconduit extension 22. As here shown, the bag is formed with a sleeveportion 23 secured to the extension 22 by means of a C clamp 24 having amanually operative thumbscrew 26.

Means 27 is also mounted on the bag and is adapted to provide arestricted passage for egress of the air at a rate of flow not exceedingthe rate of flow of the pneumatic conveyor so that the bag will bemaintained in inflated condition. Preferably and as here shown, themeans 27 consists of a tube 28 secured by a clamp 29 to a sleeve portion31 in a manner similar to the connection of conduit extension 22 to thebag 11. Mounted in the tube 28 is a butterfly valve 32 which may bemanually operated by a handle 33 positioned at the exterior of the tube.The butterfly valve 32 should be regulated to allow air to escape inquantities sutficient to avoid blowing up the bag 11 but not suflicientto permit the bag to deflate.

FIGURE 2 of the drawings illustrates the conveyor means 16a ascomprising a pneumatic suction conduit 34 adapted for connection to ablower or the like (not shown). The grain 12 is entrained in the airbeing drawn into the intake end 36 of conduit 34 and passes through theconduit to a suitable storage bin.

As a feature of the present invention, air is added to the bag 11 insuflicient quantities to maintain the bag in inflated condition whilethe conduit 34 is removing the grain. This is here accomplished by asmaller conduit 37 through which high-pressure air is forced insufiicient volume to make up the quantities of air drawn from the bagthrough the conduit 34.

I have found that the operation of the pneumatic conveyor conduit 34 maybe significantly facilitated by providing a nozzle 38 on the end ofconduit 37, the nozzle being formed for directing a blast ofhigh-pressure air against the grain 12. This stirs up the grain in theends of the compartment and aids in entraining it in the air enteringthe pneumatic conveyor 34.

A modified form of the invention is illustrated in FIG- URE 4 in whichthe conveyor means 16b is mechanical in nature as contrasted to thepneumatic conveyors illustrated in FIGURES 1 and 2. It should beapparent that the described inflation of the bag 11 is equally effectivein connection with mechanical conveyors. The supporting of the walls ofthe bag in distended condition permits the operator to direct the end ofthe conveyor to the correct location to effect complete removal of thegrain.

The mechanical conveyor means 16b illustrated in FIG- URE 4 is of aconventional type and consists of an auger 39 rotatable in a trough 41.The trough 41 should be mounted for free swinging movement so that itsintake end 42 may be moved to correct position for unloading all of thegrain. In this connection it should be noted that should the mechanicalconveyor means 16b be ineffective for removing the last remnants of thegrain, the bag 11 may be collapsed and drawn out through the accesshatch 43 in the dome 44 of the railway car 17.

In carrying out the method of the present invention, the compartment tobe used is provided with a separate flexible plastic bag liner. Theflowable material is then conveyed into the bag liner while the interiorof the latter is maintained at a pressure higher than atmosphericpressure so as to support the bag liner in distended condition. At thedestination the bag liner is again inflated and held in distendedcondition while the flowable material is being removed therefrom.

The method and apparatus of the present invention is thus well suitedfor preventing contamination of materials even though shipped in thesame compartment as some incompatible material. Ordinarily it iscontemplated that the incompatible materials Will occupy the compartmentat different times and the major problem will be to prevent any residueremaining in the compartment from contaminating subsequent shipments.However it should be appreciated that the present invention is alsoeffective to prevent the compartment from becoming contaminated in thefirst place. Moreover, the present invention can be adapted to permitshipping of incompatihle materials in the same compartment at the sametime. This may be done very simply by providing more than one of thebags 11, with each bag having its own conveying and inflating means.

I claim:

1. An apparatus for transporting flowable materials in an elongatedtank-like shipping compartment having a limited access, comprising a bagadapted for containing a flowable material and having thin flexiblewalls impervious to vapors and formed for positioning within thecompartment, a pneumatic conveyor having a flexible suction conduitextending into said bag and formed for drawing air and the materialentrained thereon from said bag, and means for adding air to theinterior of said bag at a rate of flow not less than the rate of flow ofsaid pneumatic conveyor whereby the bag will be maintained in inflatedcondition during removal of the said material, said conduitincorporating a passage for high-pressure air terminating in a nozzlepositioned inside of said bag, said nozzle being formed for directing ablast of high-pressure air issuing therethrough against the mate rial toaid in stirring up the material in the ends of said compartment andentraining it in the air entering said pneumatic conveyor.

2. An apparatus for transporting flowable materials in an elongatedtank-like shipping compartment, comprising a flexible plastic bagadapted for containing a flowable material having Walls impervious tovapors and formed in substantial matching configuration at the end ofthe compartment, a conveyor for moving materials into and out of saidbag through said limited access, and penumatic means associated withsaid conveyor and simultaneously operative therewith for maintaining thebag in an inflated condition as material is moved into and out of saidbag.

3. The apparatus defined in claim 2, in which theconveyor utilized forremoval of material is a mechanical conveyor.

4. The apparatus defined in claim 2, in which the conveyor utilized forremoval of material is a pneumatic conveyor extending into said bag andformed for blowing air and a flowa-ble material entrained thereon intosaid bag, and the means for maintaining the bag in inflated condition isa restricted passage for egress of air blown into the bag by thepneumatic conveyor.

5. The apparatus defined in claim 2, in which the conveyor and means formaintaining the bag in inflated condition includes a pneumatic conveyorhaving a flexible suction conduit extending into said bag and formed fordrawing air and the material entrained thereon from said bag, and meansfor adding air to the interior of said bag at a rate of flow not lessthan the rate of flow of said pneumatic conveyor whereby the bag will bemaintained in inflated condition during removal of the said material,said conduit incorporating a passage for high-pressure air terminatingin a nozzle positioned inside of said bag, said nozzle being formed fordirecting a blast of high-pressure air issuing therethrough against thematerial to aid in stirring up the material in the ends of saidcompartment and entraining it in the air entering said pneumaticconveyor.

6. In a railroad tankcar having -a tank with limited access, incombination, a flexible plastic bag adapted for containing a flowablematerial having walls impervious to vapors and formed in substantialmatching configuration at the end of the compartment, a conveyor formoving materials into and out of said bag through said limit ed access,and pneumatic means associated with said conveyor and simultaneouslyoperative therewith for maintaining the bag in an inflated condition asmaterial is moved into and out of said bag.

7. The method of shipping flowable materials in a shipping compartmenthaving a limited access, comprising the steps of inserting an air-tightflexible plastic bag liner in said compartment, inflating the bag liner,adding the material to be shipped while maintaining the bag in inflatedcondition, transporting the container and contents to a shippingdestination, inflating the liner at the shipping destination andremoving the material from the bag While the liner is maintained in aninflated condition.

8. The method of shipping flowable materials in a shipping compartmenthaving a limited access, comprising the steps of inserting an air-tightflexible plastic bag liner having matching configuration with thecontainer in said compartment, inflating the bag liner to extend theliner in position against the container, adding the material to beshipped while maintaining the bag in inflated condition, transportingthe container and contents to a shipping destination, inflating theliner at the shipping destination and removing the material from the bagwith a pneumatic conveyor while blowing a stream of air into the linerto dislodge and entrain material while simultaneously maintaining theliner in an inflated condition.

References Cited in the file of this patent UNITED STATES PATENTS1,498,612 Collingwood June 24, 1924 2,394,607 Gray Feb. 12, 19462,950,146 Lease Aug. 23, 1960 2,991,906 Eligonlachvili July 11, 19613,005,317 Bunn Oct. 24, 1961 FOREIGN PATENTS 484,440 Canada July 1, 1952

2. AN APPARATUS FOR TRANSPORTING FLOWABLE MATERIALS IN AN ELONGATEDTANK-LIKE SHIPPING COMPARTMENT, COMPRISING A FLEXIBLE PLASTIC BAGADAPTED FOR CONTAINING A FLOWABLE MATERIAL HAVING WALLS IMPERVIOUS TOVAPORS AND FORMED IN SUBSTANTIAL MATCHING CONFIGURATION AT THE END OFTHE COMPARTMENT, A CONVEYOR FOR MOVING MATERIALS INTO AND OUT OF SAIDBAG THROUGH SAID LIMITED ACCESS, AND PENUMATIC MEANS ASSOCIATED WITHSAID CONVEYOR AND SIMULTANEOUSLY OPERATIVE THEREWITH FOR MAINTAINING THEBAG IN AN INFLATED CONDITION AS MATERIAL IS MOVED INTO AND OUT OF SAIDBAG.